Beus, S.S., 1979, Trail log--third day: South Kaibab Trail, Grand Canyon, Arizona, in Beus, S.S., and Rawson, R.R., eds., Carboniferous stratigraphy in the Grand Canyon country, northern Arizona and southern Nevada, International Congress of Carboniferous Stratigraphy and Geology, 9th, Field Trip 13: American Geological Institute Selected Guidebook Series no. 2, p. 16-19.